Field of the Invention
The present invention relates to an object detecting apparatus, an object detecting method, and a program for detecting a main object from an input image.
Description of the Related Art
Generally, in an image such as a photograph or the like, a main object is such an object (human, body, or the like) that the photographer wants to fetch it into an image. However, since an intention of the photographer can be known only by the photographer himself, when the third person intends to identify the main object, it is necessary to presume the intention of the photographer. It is, therefore, very difficult to accurately detect the main object matched with the intention of the photographer.
Therefore, in the related arts, as a method of detecting the main object without presuming the intention of the photographer, methods of detecting the main object from an image on the basis of a salient region in the image have been examined. Those methods can be regarded as a detecting method of the main object based on such an experience that the main object is salient among many images.
Although the methods of detecting the main object from the image on the basis of the salient region in the image have been examined as a method of detecting the main object as mentioned above, those methods have the following problems.
First, in the case of identifying the main object region on the basis of the salient region, there is such a problem that even if the region is salient, how to handle a region which is not the main object is unclear. Since the desired main object of the photographer can be known only by the photographer himself as mentioned above, the region which is not the main object can be also known only by the photographer himself. Therefore, the Official Gazette of Japanese Patent Application Laid-Open No. 2000-207564 also discloses a method of determining a main object region in consideration of not only a saliency but also a position and a size in an image or information showing what is in its salient region.
Generally, in many cases, an object to detect a main object is to realize a specific application by using its detection result. For example, in the case of presuming a case where a function to detect a main object is used in a digital camera or the like, the following applications are considered. That is, there is considered a method whereby by auto-focusing (AF) on a main object region, photographing of a picture matched with an intention of the photographer is enabled. Or, such an application that even if a main object is moved, by auto-tracking on a main object region, a shutter chance is not lost or the like can be presumed.
However, according to the prior arts, nothing is considered about a point that a detection result of the main object is evaluated from a viewpoint such as usefulness of such an application. Further, in the case of a method disclosed in the Official Gazette of Japanese Patent Application Laid-Open No. 2011-34311, there is also such a possibility that a region which is not a main object although it is salient is erroneously detected as a main object.
In consideration of the foregoing problems, it is an aspect of the invention that a detection result of an object which is useful to an application can be obtained.